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/* Cache and manage the values of registers for GDB, the GNU debugger.

   Copyright 1986, 1987, 1989, 1991, 1994, 1995, 1996, 1998, 2000, 2001

   Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 2 of the License, or

   (at your option) any later version.

   This program is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License

   along with this program; if not, write to the Free Software

   Foundation, Inc., 59 Temple Place - Suite 330,

   Boston, MA 02111-1307, USA.  */

#include "defs.h"

#include "inferior.h"

#include "target.h"

#include "gdbarch.h"

#include "gdbcmd.h"

#include "regcache.h"

#include "gdb_assert.h"

/*

 * DATA STRUCTURE

 *

 * Here is the actual register cache.

 */

/* NOTE: this is a write-through cache.  There is no "dirty" bit for

   recording if the register values have been changed (eg. by the

   user).  Therefore all registers must be written back to the

   target when appropriate.  */

/* REGISTERS contains the cached register values (in target byte order). */

char *registers;

/* REGISTER_VALID is 0 if the register needs to be fetched,

                     1 if it has been fetched, and

                    -1 if the register value was not available.

   "Not available" means don't try to fetch it again.  */

signed char *register_valid;

/* The thread/process associated with the current set of registers. */

static ptid_t registers_ptid;

/*

 * FUNCTIONS:

 */

/* REGISTER_CACHED()

   Returns 0 if the value is not in the cache (needs fetch).

          >0 if the value is in the cache.

          <0 if the value is permanently unavailable (don't ask again).  */

int

register_cached (int regnum)

{

  return register_valid[regnum];

}

/* Record that REGNUM's value is cached if STATE is >0, uncached but

   fetchable if STATE is 0, and uncached and unfetchable if STATE is <0.  */

void

set_register_cached (int regnum, int state)

{

  register_valid[regnum] = state;

}

/* REGISTER_CHANGED

   invalidate a single register REGNUM in the cache */

void

register_changed (int regnum)

{

  set_register_cached (regnum, 0);

}

/* If REGNUM >= 0, return a pointer to register REGNUM's cache buffer area,

   else return a pointer to the start of the cache buffer.  */

char *

register_buffer (int regnum)

{

  if (regnum < 0)

    return registers;

  else

    return &registers[REGISTER_BYTE (regnum)];

}

/* Return whether register REGNUM is a real register.  */

static int

real_register (int regnum)

{

  return regnum >= 0 && regnum < NUM_REGS;

}

/* Return whether register REGNUM is a pseudo register.  */

static int

pseudo_register (int regnum)

{

  return regnum >= NUM_REGS && regnum < NUM_REGS + NUM_PSEUDO_REGS;

}

/* Fetch register REGNUM into the cache.  */

static void

fetch_register (int regnum)

{

  if (real_register (regnum))

    target_fetch_registers (regnum);

  else if (pseudo_register (regnum))

    FETCH_PSEUDO_REGISTER (regnum);

}

/* Write register REGNUM cached value to the target.  */

static void

store_register (int regnum)

{

  if (real_register (regnum))

    target_store_registers (regnum);

  else if (pseudo_register (regnum))

    STORE_PSEUDO_REGISTER (regnum);

}

/* Low level examining and depositing of registers.

   The caller is responsible for making sure that the inferior is

   stopped before calling the fetching routines, or it will get

   garbage.  (a change from GDB version 3, in which the caller got the

   value from the last stop).  */

/* REGISTERS_CHANGED ()

   Indicate that registers may have changed, so invalidate the cache.  */

void

registers_changed (void)

{

  int i;

  registers_ptid = pid_to_ptid (-1);

  /* Force cleanup of any alloca areas if using C alloca instead of

     a builtin alloca.  This particular call is used to clean up

     areas allocated by low level target code which may build up

     during lengthy interactions between gdb and the target before

     gdb gives control to the user (ie watchpoints).  */

  alloca (0);

  for (i = 0; i < NUM_REGS; i++)

    set_register_cached (i, 0);

  /* Assume that if all the hardware regs have changed,

     then so have the pseudo-registers.  */

  for (i = NUM_REGS; i < NUM_REGS + NUM_PSEUDO_REGS; i++)

    set_register_cached (i, 0);

  if (registers_changed_hook)

    registers_changed_hook ();

}

/* REGISTERS_FETCHED ()

   Indicate that all registers have been fetched, so mark them all valid.  */

void

registers_fetched (void)

{

  int i;

  for (i = 0; i < NUM_REGS; i++)

    set_register_cached (i, 1);

  /* Do not assume that the pseudo-regs have also been fetched.

     Fetching all real regs might not account for all pseudo-regs.  */

}

/* read_register_bytes and write_register_bytes are generally a *BAD*

   idea.  They are inefficient because they need to check for partial

   updates, which can only be done by scanning through all of the

   registers and seeing if the bytes that are being read/written fall

   inside of an invalid register.  [The main reason this is necessary

   is that register sizes can vary, so a simple index won't suffice.]

   It is far better to call read_register_gen and write_register_gen

   if you want to get at the raw register contents, as it only takes a

   regnum as an argument, and therefore can't do a partial register

   update.

   Prior to the recent fixes to check for partial updates, both read

   and write_register_bytes always checked to see if any registers

   were stale, and then called target_fetch_registers (-1) to update

   the whole set.  This caused really slowed things down for remote

   targets.  */

/* Copy INLEN bytes of consecutive data from registers

   starting with the INREGBYTE'th byte of register data

   into memory at MYADDR.  */

void

read_register_bytes (int in_start, char *in_buf, int in_len)

{

  int in_end = in_start + in_len;

  int regnum;

  char *reg_buf = alloca (MAX_REGISTER_RAW_SIZE);

  /* See if we are trying to read bytes from out-of-date registers.  If so,

     update just those registers.  */

  for (regnum = 0; regnum < NUM_REGS + NUM_PSEUDO_REGS; regnum++)

    {

      int reg_start;

      int reg_end;

      int reg_len;

      int start;

      int end;

      int byte;

      if (REGISTER_NAME (regnum) == NULL || *REGISTER_NAME (regnum) == '\0')

        continue;

      reg_start = REGISTER_BYTE (regnum);

      reg_len = REGISTER_RAW_SIZE (regnum);

      reg_end = reg_start + reg_len;

      if (reg_end <= in_start || in_end <= reg_start)

        /* The range the user wants to read doesn't overlap with regnum.  */

        continue;

      /* Force the cache to fetch the entire register. */

      read_register_gen (regnum, reg_buf);

      /* Legacy note: This function, for some reason, allows a NULL

         input buffer.  If the buffer is NULL, the registers are still

         fetched, just the final transfer is skipped. */

      if (in_buf == NULL)

        continue;

      /* start = max (reg_start, in_start) */

      if (reg_start > in_start)

        start = reg_start;

      else

        start = in_start;

      /* end = min (reg_end, in_end) */

      if (reg_end < in_end)

        end = reg_end;

      else

        end = in_end;

      /* Transfer just the bytes common to both IN_BUF and REG_BUF */

      for (byte = start; byte < end; byte++)

        {

          in_buf[byte - in_start] = reg_buf[byte - reg_start];

        }

    }

}

/* Read register REGNUM into memory at MYADDR, which must be large

   enough for REGISTER_RAW_BYTES (REGNUM).  Target byte-order.  If the

   register is known to be the size of a CORE_ADDR or smaller,

   read_register can be used instead.  */

static void

legacy_read_register_gen (int regnum, char *myaddr)

{

  gdb_assert (regnum >= 0 && regnum < (NUM_REGS + NUM_PSEUDO_REGS));

  if (! ptid_equal (registers_ptid, inferior_ptid))

    {

      registers_changed ();

      registers_ptid = inferior_ptid;

    }

  if (!register_cached (regnum))

    fetch_register (regnum);

  memcpy (myaddr, register_buffer (regnum),

          REGISTER_RAW_SIZE (regnum));

}

void

regcache_read (int rawnum, char *buf)

{

  gdb_assert (rawnum >= 0 && rawnum < NUM_REGS);

  /* For moment, just use underlying legacy code. Ulgh!!! */

  legacy_read_register_gen (rawnum, buf);

}

void

read_register_gen (int regnum, char *buf)

{

  if (! gdbarch_register_read_p (current_gdbarch))

    {

      legacy_read_register_gen (regnum, buf);

      return;

    }

  gdbarch_register_read (current_gdbarch, regnum, buf);

}

/* Write register REGNUM at MYADDR to the target.  MYADDR points at

   REGISTER_RAW_BYTES(REGNUM), which must be in target byte-order.  */

static void

legacy_write_register_gen (int regnum, char *myaddr)

{

  int size;

  gdb_assert (regnum >= 0 && regnum < (NUM_REGS + NUM_PSEUDO_REGS));

  /* On the sparc, writing %g0 is a no-op, so we don't even want to

     change the registers array if something writes to this register.  */

  if (CANNOT_STORE_REGISTER (regnum))

    return;

  if (! ptid_equal (registers_ptid, inferior_ptid))

    {

      registers_changed ();

      registers_ptid = inferior_ptid;

    }

  size = REGISTER_RAW_SIZE (regnum);

  /* If we have a valid copy of the register, and new value == old value,

     then don't bother doing the actual store. */

  if (register_cached (regnum)

      && memcmp (register_buffer (regnum), myaddr, size) == 0)

    return;

  if (real_register (regnum))

    target_prepare_to_store ();

  memcpy (register_buffer (regnum), myaddr, size);

  set_register_cached (regnum, 1);

  store_register (regnum);

}

void

regcache_write (int rawnum, char *buf)

{

  gdb_assert (rawnum >= 0 && rawnum < NUM_REGS);

  /* For moment, just use underlying legacy code. Ulgh!!! */

  legacy_write_register_gen (rawnum, buf);

}

void

write_register_gen (int regnum, char *buf)

{

  if (! gdbarch_register_write_p (current_gdbarch))

    {

      legacy_write_register_gen (regnum, buf);

      return;

    }

  gdbarch_register_write (current_gdbarch, regnum, buf);

}

/* Copy INLEN bytes of consecutive data from memory at MYADDR

   into registers starting with the MYREGSTART'th byte of register data.  */

void

write_register_bytes (int myregstart, char *myaddr, int inlen)

{

  int myregend = myregstart + inlen;

  int regnum;

  target_prepare_to_store ();

  /* Scan through the registers updating any that are covered by the

     range myregstart<=>myregend using write_register_gen, which does

     nice things like handling threads, and avoiding updates when the

     new and old contents are the same.  */

  for (regnum = 0; regnum < NUM_REGS + NUM_PSEUDO_REGS; regnum++)

    {

      int regstart, regend;

      regstart = REGISTER_BYTE (regnum);

      regend = regstart + REGISTER_RAW_SIZE (regnum);

      /* Is this register completely outside the range the user is writing?  */

      if (myregend <= regstart || regend <= myregstart)

        /* do nothing */ ;

      /* Is this register completely within the range the user is writing?  */

      else if (myregstart <= regstart && regend <= myregend)

        write_register_gen (regnum, myaddr + (regstart - myregstart));

      /* The register partially overlaps the range being written.  */

      else

        {

          char *regbuf = (char*) alloca (MAX_REGISTER_RAW_SIZE);

          /* What's the overlap between this register's bytes and

             those the caller wants to write?  */

          int overlapstart = max (regstart, myregstart);

          int overlapend   = min (regend,   myregend);

          /* We may be doing a partial update of an invalid register.

             Update it from the target before scribbling on it.  */

          read_register_gen (regnum, regbuf);

          memcpy (registers + overlapstart,

                  myaddr + (overlapstart - myregstart),

                  overlapend - overlapstart);

          store_register (regnum);

        }

    }

}

/* Return the contents of register REGNUM as an unsigned integer.  */

ULONGEST

read_register (int regnum)

{

  char *buf = alloca (REGISTER_RAW_SIZE (regnum));

  read_register_gen (regnum, buf);

  return (extract_unsigned_integer (buf, REGISTER_RAW_SIZE (regnum)));

}

ULONGEST

read_register_pid (int regnum, ptid_t ptid)

{

  ptid_t save_ptid;

  int save_pid;

  CORE_ADDR retval;

  if (ptid_equal (ptid, inferior_ptid))

    return read_register (regnum);

  save_ptid = inferior_ptid;

  inferior_ptid = ptid;

  retval = read_register (regnum);

  inferior_ptid = save_ptid;

  return retval;

}

/* Return the contents of register REGNUM as a signed integer.  */

LONGEST

read_signed_register (int regnum)

{

  void *buf = alloca (REGISTER_RAW_SIZE (regnum));

  read_register_gen (regnum, buf);

  return (extract_signed_integer (buf, REGISTER_RAW_SIZE (regnum)));

}

LONGEST

read_signed_register_pid (int regnum, ptid_t ptid)

{

  ptid_t save_ptid;

  LONGEST retval;

  if (ptid_equal (ptid, inferior_ptid))

    return read_signed_register (regnum);

  save_ptid = inferior_ptid;

  inferior_ptid = ptid;

  retval = read_signed_register (regnum);

  inferior_ptid = save_ptid;

  return retval;

}

/* Store VALUE into the raw contents of register number REGNUM.  */

void

write_register (int regnum, LONGEST val)

{

  void *buf;

  int size;

  size = REGISTER_RAW_SIZE (regnum);

  buf = alloca (size);

  store_signed_integer (buf, size, (LONGEST) val);

  write_register_gen (regnum, buf);

}

void

write_register_pid (int regnum, CORE_ADDR val, ptid_t ptid)

{

  ptid_t save_ptid;

  if (ptid_equal (ptid, inferior_ptid))

    {

      write_register (regnum, val);

      return;

    }

  save_ptid = inferior_ptid;

  inferior_ptid = ptid;

  write_register (regnum, val);

  inferior_ptid = save_ptid;

}

/* SUPPLY_REGISTER()

   Record that register REGNUM contains VAL.  This is used when the

   value is obtained from the inferior or core dump, so there is no

   need to store the value there.

   If VAL is a NULL pointer, then it's probably an unsupported register.

   We just set its value to all zeros.  We might want to record this

   fact, and report it to the users of read_register and friends.  */

void

supply_register (int regnum, char *val)

{

#if 1

  if (! ptid_equal (registers_ptid, inferior_ptid))

    {

      registers_changed ();

      registers_ptid = inferior_ptid;

    }

#endif

  set_register_cached (regnum, 1);

  if (val)

    memcpy (register_buffer (regnum), val,

            REGISTER_RAW_SIZE (regnum));

  else

    memset (register_buffer (regnum), '\000',

            REGISTER_RAW_SIZE (regnum));

  /* On some architectures, e.g. HPPA, there are a few stray bits in

     some registers, that the rest of the code would like to ignore.  */

  /* NOTE: cagney/2001-03-16: The macro CLEAN_UP_REGISTER_VALUE is

     going to be deprecated.  Instead architectures will leave the raw

     register value as is and instead clean things up as they pass

     through the method gdbarch_register_read() clean up the

     values. */

#ifdef CLEAN_UP_REGISTER_VALUE

  CLEAN_UP_REGISTER_VALUE (regnum, register_buffer (regnum));

#endif

}

/* read_pc, write_pc, read_sp, write_sp, read_fp, write_fp, etc.

   Special handling for registers PC, SP, and FP.  */

/* NOTE: cagney/2001-02-18: The functions generic_target_read_pc(),

   read_pc_pid(), read_pc(), generic_target_write_pc(),

   write_pc_pid(), write_pc(), generic_target_read_sp(), read_sp(),

   generic_target_write_sp(), write_sp(), generic_target_read_fp(),

   read_fp(), generic_target_write_fp(), write_fp will eventually be

   moved out of the reg-cache into either frame.[hc] or to the

   multi-arch framework.  The are not part of the raw register cache.  */

/* This routine is getting awfully cluttered with #if's.  It's probably

   time to turn this into READ_PC and define it in the tm.h file.

   Ditto for write_pc.

   1999-06-08: The following were re-written so that it assumes the

   existence of a TARGET_READ_PC et.al. macro.  A default generic

   version of that macro is made available where needed.

   Since the ``TARGET_READ_PC'' et.al. macro is going to be controlled

   by the multi-arch framework, it will eventually be possible to

   eliminate the intermediate read_pc_pid().  The client would call

   TARGET_READ_PC directly. (cagney). */

CORE_ADDR

generic_target_read_pc (ptid_t ptid)

{

#ifdef PC_REGNUM

  if (PC_REGNUM >= 0)

    {

      CORE_ADDR pc_val = ADDR_BITS_REMOVE ((CORE_ADDR) read_register_pid (PC_REGNUM, ptid));

      return pc_val;

    }

#endif

  internal_error (__FILE__, __LINE__,

                  "generic_target_read_pc");

  return 0;

}

CORE_ADDR

read_pc_pid (ptid_t ptid)

{

  ptid_t saved_inferior_ptid;

  CORE_ADDR pc_val;

  /* In case ptid != inferior_ptid. */

  saved_inferior_ptid = inferior_ptid;

  inferior_ptid = ptid;

  pc_val = TARGET_READ_PC (ptid);

  inferior_ptid = saved_inferior_ptid;

  return pc_val;

}

CORE_ADDR

read_pc (void)

{

  return read_pc_pid (inferior_ptid);

}

void

generic_target_write_pc (CORE_ADDR pc, ptid_t ptid)

{

#ifdef PC_REGNUM

  if (PC_REGNUM >= 0)

    write_register_pid (PC_REGNUM, pc, ptid);

  if (NPC_REGNUM >= 0)

    write_register_pid (NPC_REGNUM, pc + 4, ptid);

  if (NNPC_REGNUM >= 0)

    write_register_pid (NNPC_REGNUM, pc + 8, ptid);

#else

  internal_error (__FILE__, __LINE__,

                  "generic_target_write_pc");

#endif

}

void

write_pc_pid (CORE_ADDR pc, ptid_t ptid)

{

  ptid_t saved_inferior_ptid;

  /* In case ptid != inferior_ptid. */

  saved_inferior_ptid = inferior_ptid;

  inferior_ptid = ptid;

  TARGET_WRITE_PC (pc, ptid);

  inferior_ptid = saved_inferior_ptid;

}

void

write_pc (CORE_ADDR pc)

{

  write_pc_pid (pc, inferior_ptid);

}

/* Cope with strage ways of getting to the stack and frame pointers */

CORE_ADDR

generic_target_read_sp (void)

{

#ifdef SP_REGNUM

  if (SP_REGNUM >= 0)

    return read_register (SP_REGNUM);

#endif

  internal_error (__FILE__, __LINE__,

                  "generic_target_read_sp");

}

CORE_ADDR

read_sp (void)

{

  return TARGET_READ_SP ();

}

void

generic_target_write_sp (CORE_ADDR val)

{

#ifdef SP_REGNUM

  if (SP_REGNUM >= 0)

    {

      write_register (SP_REGNUM, val);

      return;

    }

#endif

  internal_error (__FILE__, __LINE__,

                  "generic_target_write_sp");

}

void

write_sp (CORE_ADDR val)

{

  TARGET_WRITE_SP (val);

}

CORE_ADDR

generic_target_read_fp (void)

{

#ifdef FP_REGNUM

  if (FP_REGNUM >= 0)

    return read_register (FP_REGNUM);

#endif

  internal_error (__FILE__, __LINE__,

                  "generic_target_read_fp");

}

CORE_ADDR

read_fp (void)

{

  return TARGET_READ_FP ();

}

void

generic_target_write_fp (CORE_ADDR val)

{

#ifdef FP_REGNUM

  if (FP_REGNUM >= 0)

    {

      write_register (FP_REGNUM, val);

      return;

    }

#endif

  internal_error (__FILE__, __LINE__,

                  "generic_target_write_fp");

}

void

write_fp (CORE_ADDR val)

{

  TARGET_WRITE_FP (val);

}

/* ARGSUSED */

static void

reg_flush_command (char *command, int from_tty)

{

  /* Force-flush the register cache.  */

  registers_changed ();

  if (from_tty)

    printf_filtered ("Register cache flushed.\n");

}

static void

build_regcache (void)

{

  /* We allocate some extra slop since we do a lot of memcpy's around

     `registers', and failing-soft is better than failing hard.  */

  int sizeof_registers = REGISTER_BYTES + /* SLOP */ 256;

  int sizeof_register_valid =

    (NUM_REGS + NUM_PSEUDO_REGS) * sizeof (*register_valid);